Formation of characters for the stamping of bodies intended to be hardened by heat treatment



1,93%357 STAMPING OF BODIES Y @Ci. 2 5w, l n H R A FORMATION OF CHARACTERS FOR..THE

INTENDED TO BE HARDENED BY HEAT TREATMENT Filed July 18, 1935 INVENTOR HAAKON STYR/ ATTORNEY Patented Oct. 24, 1933 UNITED STATES FORMATION OF CHARACTERS FOR THE STAMPING OF BODIES INTENDED TO BE HARDENED BY HEAT TREATMENT Haakon Styri, Philadelphia, Pa., assignor to The Hess-Bright Manufacturing Company, Philadelphia, Pa., a corporation of Pennsyl- Vania Application July 18, 1933. Serial No. 680,921

5 Claims. (01. 101-28) This invention relates to the form of the stamps used for impressing identifying characters and marks in steel bodies, particularly those which are subsequently to be hardened by heat treatment. Broadly stated, the invention consists in rounding the cutting edge of the stamp and breaking the longer lines of the characters.

The principal reason for breaking the lines of letters and figures is that articles of steel which are hardened by. being heated and quenched sometimes develop cracks during the hardening process or shortly afterwards by reason of the stamping. These so-called quenching cracks I are most frequently caused by long straight lines in stamps and especiallywhen the stamps are very sharp. The identification marks stamped in steel bodies which it is intended to heat treat must be of suificient depth that they will not be ground out in some subsequent grinding operation. In order to get sufliciently deep stamping to avoid this, the man who applies the stamp wants a sharp pointed letter which is exactly the type that would cause the trouble in hardening.

;It is, therefore, necessary to compromise somewhat on the sharpness of the cutting edge of the stamp and from my experience I find that desirable results may be obtained by forming the cutting edge on a radius of about .01.

In order to further reduce danger from long lines in the cutting edges I have proposed breaking these into shorter lines in addition to giving the cutting edge a radius. Incidental to this method of breaking lines and rounding, it is of certain benefit to the stamp manufacturer that intersecting lines can be discontinued at the intersections because this will facilitate the running out of the scraper in giving radius to the cutting edge.

The new method of designing letters and characters, therefore, serves a double purpose: getting better condition to resist starting of quenching cracks in the steel and to facilitate manufacturing of the letters in the stamp.

In the drawing accompanying this application I have illustrated some identifying characters and some representations of stamping dies carrying out my invention in which drawing:

Figure 1 as formed by my improved stamps represents the primary numerals,

Fig. 2 as formed by my improved stamps represents the letters of the alphabet and some additional characters,

Fig. 3 is an enlarged elevational view of the stamp employed for making the letter I in such alphabet, and

Fig. 4 is a cross section thereof.

The character represented in the drawing are considerably larger than those which will generally be employed. An illustration of an industry in which I have made use of this discovery is that of stamping the ends of the rings of anti-friction bearings. The height of such characters varies in the dilierent sizes of rings but not necessarily in proportion to the size. A height of character which is used in a good many anti-friction bearings is and It will be seen by reference to Figures 3 and 4 that the cutting edge 6 is rounded from side to side, and for the sizes given, and it will be formed on a radius of about .010". By reference to Figure 3 it will also be seen that the ends of the cutting edge are also round on about the same radius.

By having a blunt cutting edge, preferably on which is formed on a radius, the penetration of the stamp into the unhardened steel does not cause conditions which are apt to develop quenching or hardening cracks as does a sharp edge. Not only is this true of the formation of the portion which forms the body of the character but also is true of the ends"? of each section of the character.

For the purpose of preventing cracks starting by reason of long indentation I have found it desirable to break the long lines as illustrated in the drawing, and particularly at 8.

Not only is it found desirable to round off the ends of each body section of the stamp for forming the character. for the purpose of preventing the origination of cracks but it also is of assistance to the stamp maker in shaping the die.

Having thus described my invention I claim and .desire to secure by Letters Patent:

1. A stamp of the character specified, comprising a body portion and an impressing edge, such edge being rounded in across sectional direction.

2. A stamp of the character specified, comprising a body portion and an impressing edge, such edge being formed on a radius in a cross direction.

sectional.

5. A set of stamps embodying the characters including numerals and letters of the alphabet and designed for use in forming characters in steel which is intended to be hardened by heat treatment, each of the stamps having its cutting edge rounded and the longer lines of the characters broken across the length.

HAAKON STYRI. 

